Phase 6: QA fixes for Lighthouse and navigation

- Map is a titled iframe (accessibility); drop @next/third-parties
- "Services" nav toggle is a real button with aria-expanded (SEO
  crawlable-anchors, accessibility)
- Hero images use default quality; page-header image is preloaded (LCP)
- Mobile services submenu no longer clips its last item

Mobile Lighthouse: / 94/100/100/100, /services/computer-repair
96/100/100/100, /areas/henderson 97/100/100/100, /contact 95/100/100/100
(performance/accessibility/best practices/SEO).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/app/page.js

@@ -120,7 +120,6 @@ export default function Home() {
               src={bgimage}
               alt=""
               placeholder="blur"
-              quality={100}
               fill
               priority
               sizes="100vw"